Real time assessment of ablation from electrocardiogram signals

Abstract

An apparatus includes an intra-body probe and a processor. The intra-body probe includes an electrode, which is configured to contact tissue in a heart. The processor is configured to receive an electrical signal from the electrode, to distinguish a local component, due to the tissue with which the electrode is in contact, in the electrical signal from a remote-field contribution to the signal, and to control a therapeutic procedure applied to the tissue responsively to the distinguished local component.

The invention claimed is: 
     
       1. An apparatus, comprising:
 an intra-body probe comprising an electrode, which is configured to contact tissue in a heart, wherein the electrode is configured to receive ECG signals and apply a radio frequency ablation signal; and 
 a processor, which is configured to receive an electrical signal from the electrode, the electrical signal comprising a local component and a remote-field contribution, to distinguish the local component, due to the tissue with which the electrode is in contact, in the electrical signal from the remote-field contribution to the signal, and to control a therapeutic procedure applied to the tissue responsively to the distinguished local component. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the therapeutic procedure comprises cardiac ablation therapy. 
     
     
       3. The apparatus according to  claim 1 , wherein the intra-body probe comprises an additional electrode that is configured to apply an ablation signal to the heart tissue. 
     
     
       4. The apparatus according to  claim 1 , wherein the electrode applies an ablation signal to the tissue in the heart. 
     
     
       5. The apparatus according to  claim 1 , wherein the signal comprises a received electrocardiogram (ECG) signal. 
     
     
       6. The apparatus according to  claim 1 , wherein the local component is in response to cardiac electrical activity generated in the heart within a target ablation region, and the remote-field contribution is in response to cardiac electrical activity generated in the heart outside the target ablation region. 
     
     
       7. The apparatus according to  claim 1 , wherein the processor is configured to distinguish the local component by identifying one or more time intervals in the received signal in response to a change in the received signal. 
     
     
       8. The apparatus according to  claim 7 , wherein the processor is configured to distinguish the remote-field contribution by detecting no change in the received signal in one or more additional time intervals outside of the one or more identified time intervals. 
     
     
       9. The apparatus according to  claim 7 , wherein the processor is configured to initiate a termination of an ablation procedure by detecting that the signal within the one or more identified time intervals no longer changes during to successive ablation cycles. 
     
     
       10. A method, comprising:
 receiving an electrical signal from an intra-body probe comprising an electrode configured to contact tissue in a heart, the electrical signal comprising a local component and a remote-field contribution; 
 distinguishing the local component, due to the tissue with which the electrode is in contact, in the electrical signal from the remote-field contribution to the signal; 
 configuring the electrode to receive ECG signals and apply a radio frequency ablation signal and 
 controlling a therapeutic procedure applied to the tissue responsively to the distinguished local component, wherein the therapeutic procedure comprises RF ablation. 
 
     
     
       11. The method according to  claim 10 , wherein receiving the electrical signal comprises receiving an electrocardiogram (ECG) signal. 
     
     
       12. The method according to  claim 10 , wherein the local component is in response to cardiac electrical activity within a target ablation region and the remote-field contribution is in response to cardiac electrical activity generated in a region of the heart outside of the target ablation region. 
     
     
       13. The method according to  claim 10 , wherein distinguishing the local component comprises identifying one or more time intervals in the received signal in response to a change in the received signal. 
     
     
       14. The method according to  claim 13 , wherein distinguishing the remote-field contribution comprises detecting no change in the received signal in one or more additional time intervals outside of the one or more identified time intervals. 
     
     
       15. The method according to  claim 14 , wherein controlling the therapeutic procedure comprises initiating a termination of a cardiac ablation procedure in response to detecting that the signal within the identified time intervals no longer changes during to successive ablation cycles.